The commercial deep‐sea penaeid shrimp genus Parapenaeus contains 15 species, three subspecies and two forms in the Indo‐West Pacific and the Atlantic. Novel nucleotide sequence data from five different genes (COI, 16S, 12S, NaK and PEPCK) were collected to estimate phylogenetic relationships and taxonomic status amongst all but one subspecies in this genus. The phylogenetic results only support two of the four species groups previously proposed for this genus and indicate an evolution direction of the genital organs from simple to complex. The present results suggest that Parapenaeus originated in the shallow waters of the West Pacific with subsequent migration to the deep sea and the Atlantic. The molecular data reveal that there was probably misidentification of females between Parapenaeus australiensis and Parapenaeus ruberoculatus, with females previously assigned as P. australiensis likely being the females of P. ruberoculatus, while material identified as P. australiensis forma nodosa being the true P. australiensis females. On the other hand, Parapenaeus longipes forma denticulata truly represents a variation of the same species, while the subspecies Parapenaeus fissuroides indicus warrants a specific rank.

Metapenaeopsis Bouvier, 1905 is the most diverse genus within Penaeidae. Metapenaeopsis shrimps exhibited subtle morphological differences, which make identification a difficult task based on taxonomic keys alone. In this study, we carried out DNA barcoding and phylogenetic analyses to examine taxonomy and phylogeny of genus Metapenaeopsis based on mitochondrial (COI) and nuclear (PEPCK and NaK) genes. Despite limited performance of DNA barcoding in delineating Metapenaeopsis shrimps, it questioned the taxonomic status of the two subspecies, Metapenaeopsis mogiensis intermedia and Metapenaeopsis mogiensis mogiensis, as well as three separate species: Metapenaeopsis provocatoria longirostris, Metapenaeopsis quinquedentata and Metapenaeopsis velutina. The major pattern of relationships between all studied taxa of Metapenaeopsis was similar across all analytical methods in which species with one-valved petasma were genetically distinct from those with two-valved petasma. As expected from morphology, the remaining species with stridulating organ constituted a strongly supported clade. In contrast, a paraphyletic clade was resolved for species without stridulating organ which contradicts Crosnier's morphological classification scheme for Metapenaeopsis. Overall, the present molecular data indicated that the shape of petasma and stridulating organ were both phylogenetically significant morphological characters for this genus, adding further evidence for the Crosnier's proposal.

A new species of the genus Nihonotrypaea Manning & Tamaki, 1998, Nihonotrypaeahainanensis sp. n., collected from the South China Sea, is described and illustrated. It is distinguishable from Nihonotrypaeaharmandi (Bouvier, 1901), Nihonotrypaeajaponica (Ortmann, 1891), Nihonotrypaeathermophila Lin, Komai & Chan, 2007 and Nihonotrypaeamakarovi Martin, 2013 by having the elongated carpus of the male and female major cheliped. The new species is distinguishable from Nihonotrypaeapetalura (Stimpson, 1860) by the proximolower margin of the carpus of the male major cheliped bearing several small denticles.

Two new species of the genus Acutigebia (Decapoda: Gebiidae: Upogebiidae) collected from Xisha (Spratly) Islands are described. Acutigebia serrifera, new species, most closely resembles Acutigebia simsoni (Thomson, 1893), but differs markedly in the propodus of pereopod 1 with lower teeth. Acutigebia laticauda, new species, most closely resembles Acutigebia trypeta (Sakai, 1970), but differs markedly in the proportionally wider telson. This is the first record of the genus Acutigebia from the South China Sea. An updated key to the species of Acutigebia is provided.

A taxonomic survey of benthic marine animals from coastal regions of Hainan Island, South China Sea, revealed specimens of a new species of Eunice (Polychaeta: Eunicida: Eunicidae), Eunice uschakovi n. sp., collected from the intertidal zone. The species belongs to the group of Eunice that has yellow tridentate subacicular hooks and branchiae scattered over an extensive region of the body. It resembles E. miurai and E. havaica in having both bidentate and tridentate falcigers, but can be readily distinguished by branchial features. Comparisons between E. uschakovi and the two related species are presented.

Luidia Forbes (Paxillosida: Luidiidae) are common soft bottom sea stars with 49 described species. Because of substantial morphological diversity, the taxonomy of the genus is complex and hasn’t been resolved definitely. In order to resolve general taxonomic issues, and determine species boundaries and phylogenetic relationships within the genus Luidia, the sequences of cytochrome oxidase subunit I (COI) gene from 24 specimens of Luidia, belonging to eight taxa in Chinese waters, were studied. Three sequences of two species in genus Luidia from GenBank were used to analyze the phylogenetic relationships. The molecular phylogeny exhibited three main clades, each with strong bootstrap support: Clade A including Luidia quinaria from the Sea of Japan; Clade B including seven nominal species (L. quinaria von Martens, L. yesoensis Goto, L. changi Liu, Liao and Li, L. orientalis Fisher, L. avicularia Fisher, L. longispina Sladen and L. hardwicki Gray) from Chinese waters; and Clade C including L. maculata Müller & Troschel from Chinese waters. Our molecular phylogeny results support the morphological Quinaria-Group and Alternata-Group assigned by Döderlein. Seven nominal species we sampled do not exhibit genetic distances that are large enough to recognize them as separate species. Cryptic species may exist in’ Luidia quinaria’ from the Yellow Sea and the Sea of Japan. Meaningful morphological characters need further investigation in Luidia.

A new species of the genus Mantisgebia Sakai, 2006, M. multispinosa sp. nov., collected from the South China Sea, is described and illustrated. It is readily distinguished from the other three species of the genus by the numerous spines on the cervical groove, hepatic region, and lower margins of the antennular and antennal peduncles.

A taxonomic study of Eunice species based on material deposited in the Marine Biological Museum of the Chinese Academy of Sciences (MBMCAS) including recently collected specimens from coastal regions of Hainan Island, yielded two new species: Eunice hainanensis n. sp. and E. carrerai n. sp. Both species were collected from dead coral rocks in the reefs of the coastal region of Hainan Island, northern South China Sea. Eunice hainanensis has translucent bidentate subacicular hooks and branchiae present over an extensive region of the body. Within the Eunice group possessing these characters, the new species highly resembles E. schizobranchia Claparède, 1870 in having a numerous chaetigers and a very late start of branchiae (348-570 chaetigers with branchiae from chaetigers 69-72 vs. 731 chaetigers with branchiae from chaetiger 67). However, the two species differ by the presence of the maxillary plate VI (MxVI) in the new species (vs. absent in the latter). Besides, E. hainanensis is much smaller (1.7-1.9 mm vs. 5 mm in maximal width). Eunice carrerai belongs to the Eunice group that has dark bidentate subacicular hooks and branchiae present over an extensive region of the body. It can be distinguished from similar congeners that have the branchiae starting from chaetigers 3-4 and prostomial appendages with moniliform articulations by a combination of characters such as the presence of MxVI, notopodial articulations limited to anterior chaetigers, peristomial cirri articulated and extending to anterior edge of first peristomial ring. A key to 16 species of Eunice identified from China seas in the material examined with notes on their distribution is provided. The major characters of these species are briefly summarized.

BACKGROUND:The evolutionary history and relationships of the mud shrimps (Crustacea: Decapoda: Gebiidea and Axiidea) are contentious, with previous attempts revealing mixed results. The mud shrimps were once classified in the infraorder Thalassinidea. Recent molecular phylogenetic analyses, however, suggest separation of the group into two individual infraorders, Gebiidea and Axiidea. Mitochondrial (mt) genome sequence and structure can be especially powerful in resolving higher systematic relationships that may offer new insights into the phylogeny of the mud shrimps and the other decapod infraorders, and test the hypothesis of dividing the mud shrimps into two infraorders.RESULTS:We present the complete mitochondrial genome sequences of five mud shrimps, Austinogebia edulis, Upogebia major, Thalassina kelanang (Gebiidea), Nihonotrypaea thermophilus and Neaxius glyptocercus (Axiidea). All five genomes encode a standard set of 13 protein-coding genes, two ribosomal RNA genes, 22 transfer RNA genes and a putative control region. Except for T. kelanang, mud shrimp mitochondrial genomes exhibited rearrangements and novel patterns compared to the pancrustacean ground pattern. Each of the two Gebiidea species (A. edulis and U. major) and two Axiidea species (N. glyptocercus and N. thermophiles) share unique gene order specific to their infraorders and analyses further suggest these two derived gene orders have evolved independently. Phylogenetic analyses based on the concatenated nucleotide and amino acid sequences of 13 protein-coding genes indicate the possible polyphyly of mud shrimps, supporting the division of the group into two infraorders. However, the infraordinal relationships among the Gebiidea and Axiidea, and other reptants are poorly resolved. The inclusion of mt genome from more taxa, in particular the reptant infraorders Polychelida and Glypheidea is required in further analysis.CONCLUSIONS:Phylogenetic analyses on the mt genome sequences and the distinct gene orders provide further evidences for the divergence between the two mud shrimp infraorders, Gebiidea and Axiidea, corroborating previous molecular phylogeny and justifying their infraordinal status. Mitochondrial genome sequences appear to be promising markers for resolving phylogenetic issues concerning decapod crustaceans that warrant further investigations and our present study has also provided further information concerning the mt genome evolution of the Decapoda.

The ecological environment in the Yellow Sea has changed greatly from the 1950s to 1990s and this has had significant impact on marine organisms. In this study, data on soft-sediment macrobenthos occurring in depths from 25 m to 81 m in the South Yellow Sea were used to compare changes in community structure. The agglomerative classification (CLUSTER) and multidimensional scaling (MDS) methods were applied. Five communities were recognized by cluster analysis: 1. The Yellow Sea Cold Water Mass community dominated by cold water species, which changed slightly in species composition since the 1950s; 2. The mixed community with the coexistence of cold water species and warm water species, as had been reported previously; 3. The polychaete-dominated eurythermal community in which the composition changed considerably as some dominant species disappeared or decreased; 4. The Changjiang (Yangtze) River Estuarine community, with some typical estuarine species; 5. The community affected by the Yellow Sea Warm Current. The greatest change occurred in the coastal area, which indicated that the change may be caused by human activities. Macrobenthos in the central region remained almost unchanged, particularly the cold water species shielded by the Yellow Sea Cold Water Mass. The depth, temperature and median grain size of sediments were important factors affecting the distributions of macrobenthos in the South Yellow Sea.

This dataset contains the digitized treatments in Plazi based on the original journal article Liu, Wenliang, Liu, Ruiyu (2012): A new species of the genus Austinogebia Ngoc-Ho, 2001 (Crustacea, Decapoda, Gebiidea, Upogebiidae) from northern China. Zootaxa 3243: 59-64, DOI: 10.5281/zenodo.210092

Aulactinia sinensis, a new species of sea anemone collected from the intertidal zone of Qingdao, Yellow Sea, is describedand illustrated. This species is elongated, becoming plump distally, has circumscribed sphincter, and with 48 vertical rowsof verrucae in upper column, 48 pairs of mesenteries and 96 short tentacles. It is similar in shape to A. capitata Agassizin Verrill, 1864, but distinguished by its smaller basitrichs in tentacles and larger microbasic p-mastigophores in actinopharynx and mesenterial filaments.

Aulactinia sinensis, a new species of sea anemone collected from the intertidal zone of Qingdao, Yellow Sea, is describedand illustrated. This species is elongated, becoming plump distally, has circumscribed sphincter, and with 48 vertical rowsof verrucae in upper column, 48 pairs of mesenteries and 96 short tentacles. It is similar in shape to A. capitata Agassizin Verrill, 1864, but distinguished by its smaller basitrichs in tentacles and larger microbasic p-mastigophores in actinopharynx and mesenterial filaments.

FIGURE 1. Morphology of Aulactinia sinensis sp. nov. Scale = 10 mm. A. External morphology of holotype. B. Internal morphology of holotype.